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|
package parent;
use strict;
use vars qw($VERSION);
$VERSION = '0.221';
sub import {
my $class = shift;
my $inheritor = caller(0);
if ( @_ and $_[0] eq '-norequire' ) {
shift @_;
} else {
for ( my @filename = @_ ) {
if ( $_ eq $inheritor ) {
warn "Class '$inheritor' tried to inherit from itself\n";
};
s{::|'}{/}g;
require "$_.pm"; # dies if the file is not found
}
}
{
no strict 'refs';
# This is more efficient than push for the new MRO
# at least until the new MRO is fixed
@{"$inheritor\::ISA"} = (@{"$inheritor\::ISA"} , @_);
};
};
"All your base are belong to us"
__END__
=head1 NAME
parent - Establish an ISA relationship with base classes at compile time
=head1 SYNOPSIS
package Baz;
use parent qw(Foo Bar);
=head1 DESCRIPTION
Allows you to both load one or more modules, while setting up inheritance from
those modules at the same time. Mostly similar in effect to
package Baz;
BEGIN {
require Foo;
require Bar;
push @ISA, qw(Foo Bar);
}
By default, every base class needs to live in a file of its own.
If you want to have a subclass and its parent class in the same file, you
can tell C<parent> not to load any modules by using the C<-norequire> switch:
package Foo;
sub exclaim { "I CAN HAS PERL" }
package DoesNotLoadFooBar;
use parent -norequire, 'Foo', 'Bar';
# will not go looking for Foo.pm or Bar.pm
This is equivalent to the following code:
package Foo;
sub exclaim { "I CAN HAS PERL" }
package DoesNotLoadFooBar;
push @DoesNotLoadFooBar::ISA, 'Foo';
This is also helpful for the case where a package lives within
a differently named file:
package MyHash;
use Tie::Hash;
use parent -norequire, 'Tie::StdHash';
This is equivalent to the following code:
package MyHash;
require Tie::Hash;
push @ISA, 'Tie::StdHash';
If you want to load a subclass from a file that C<require> would
not consider an eligible filename (that is, it does not end in
either C<.pm> or C<.pmc>), use the following code:
package MySecondPlugin;
require './plugins/custom.plugin'; # contains Plugin::Custom
use parent -norequire, 'Plugin::Custom';
=head1 DIAGNOSTICS
=over 4
=item Class 'Foo' tried to inherit from itself
Attempting to inherit from yourself generates a warning.
use Foo;
use parent 'Foo';
=back
=head1 HISTORY
This module was forked from L<base> to remove the cruft
that had accumulated in it.
=head1 CAVEATS
=head1 SEE ALSO
L<base>
=head1 AUTHORS AND CONTRIBUTORS
Rafaël Garcia-Suarez, Bart Lateur, Max Maischein, Anno Siegel, Michael Schwern
=head1 MAINTAINER
Max Maischein C< corion@cpan.org >
Copyright (c) 2007 Max Maischein C<< <corion@cpan.org> >>
Based on the idea of C<base.pm>, which was introduced with Perl 5.004_04.
=head1 LICENSE
This module is released under the same terms as Perl itself.
=cut
|
